Dear Vikas,

Of course, particles will dissolve, even faster than the bulk polymer, because of their relatively high surface to volume ratio. If want to keep your particles from dissolution, then you have to cross-link somehow the polymer molecules within the particles before dispersing them in such a solvent.

Regards,

Georgi

Dear Vikas,

Of course, particles will dissolve, even faster than the bulk polymer, because of their relatively high surface to volume ratio. If want to keep your particles from dissolution, then you have to cross-link somehow the polymer molecules within the particles before dispersing them in such a solvent.

Regards,

Georgi

Dear Georgi,

Thanks for answering the question. In fact I am also expecting that polymer nano particles may be dissolving in solvent. Therefore, without cross-linking they can be separated by adding non solvent or just by filtration.

yup it should, solubility is not a material property which changes from going from macro to micro but it is a thermodynamic process which is irrespective for its dimension.

Cross linking depends upon of the chemistry of the solution, not just the solvent. If you are going to use non-solvent, you would like to choose based on what do you want to get out of it. Just for separation, you directly centrifuge the NPs in the current solvent system and get the pellet.

Another way would be to evaporate the solvent by using an oven below the Glass transition of the polymer NPs assuming the solvent you have used will evaporate without being toxic

On the filtration front, it mainly depends upon the size of your NPs. I think 220nm nylon filter are usually used. If you want to filter NPs below that limit, i guess you might look into specialty filters

Dear Ankur

Thanks for commenting on question and answer. I hope y

our comments will help me in experiment.

you want to separate the polymer nanoparticles from what? anyway you need to take a solvent which does not dissolve the polymer from which your nanoparticles are composed.

for filtration, I would suggest membrane filtration

Nano particles which I want to synthesise are approximately of 100-200 nm size. Suggest me which nano membrane should I go.

you want to separate the polymer nanoparticles from what? that will be critical for selecting the membrane. The particle size is not too critical, there are enough membranes for that; again, you then also have to choose a membrane which does not get attacked by the solvent you are working in and from which you want to separate your nanoparticles

Even you cross-link the polymer to make nanoparticles, it can also dissolve if it is not very big particles, and you can recover it by precipitation in poor solvent.

Generally, the solubility parameter of cross-linked polymer nanoparticles is the same as linear polymer, which means the cross-linked particles can dissolve in the same solvent if the linear polymer can dissolve in.

M. Mackay did many works in PS nanoparticles so you can find a lot of experimental details in his papers such as:

"Effect of Ideal, Organic Nanoparticles on the Flow Properties of Linear

Polymers: Non-Einstein-like Behavior" Macromolecules 2005, 38, 8000-8011

Thanks for the paper

by the way you do not plan to prepare nanoparticles. By definition these have at least size in one dimension smaller 100 nm.

Yes, particle size controlled is in between 100-100 nm. Hence in real sence if nano particles are less than 100 nm size.  However some people call nano particles which are less than 500 nm.

Anyway  I solved the problem and able to separate particles. Thanks once again to you people for helping me to solve my problem.